Ultrasound technology is an efficient and accurate way to examine and measure internal body structures and detect bodily abnormalities. Ultrasound technology works by emitting high frequency sound waves into a region of interest. The sound waves are emitted from a probe, strike the region of interest, and then reflect back to the probe. For example, certain sound waves strike tissues or fluid in the region of interest before other sound waves do and are thus reflected back to the probe sooner than other sound waves. The ultrasound machine measures the difference in time for various ultrasonic waves to be emitted and reflected back to the transducer probe and produces a picture of the region of interest based on those time differences.
Besides producing an image of the region of interest, ultrasound is capable of determining the velocity of moving tissue and fluids. For example, an ultrasound user can observe a patient's blood as it flows through the heart, determine the speed or flow rate of the blood's movement, and whether the blood is moving towards or away from the heart.
One method of measuring velocity of moving tissue and fluid is the use of Doppler ultrasound with color mapping. Doppler ultrasound is based upon the Doppler effect. When the object reflecting the sound waves is moving, it changes the frequency of the echoes that are reflected back to the probe. A Doppler ultrasound machine measures the change in frequency of the sound wave echoes and calculates how fast a particular object is moving within the region of interest. Doppler color flow mapping utilizes color to depict the directional movement of tissue and fluid (such as blood) within the region of interest. Color flow mapping produces a two-dimensional image in color with flow towards the probe shown in one color and flow away from the probe shown in another color.
Another method for measuring the displacement of moving tissue and fluid is power Doppler imaging. Power Doppler imaging is similar to color flow mapping in that is can produce an image that shows the presence or absence of blood flow and the directional movement of the flow. Power Doppler is advantageous because it is up to five times more sensitive in detecting blood flow and other forms of tissue and fluid movement than color mapping. But, power Doppler imaging is not used to determine the velocity of the moving tissue and fluid.
Ultrasound equipment used for ultrasound imaging and treatment can be divided into three main components. First, there is a peripheral ultrasound system that comprises a probe with a transducer array or a single element for emitting ultrasound waves and equipment that produces and conditions the ultrasound waves for emission from the probe. Second, a host computer system connected to the peripheral ultrasound system serves as to interface with the ultrasound user. Specifically, the host computer comprises a keyboard or other equipment to help control the ultrasound equipment and a monitor to display the image to the user. Finally, known ultrasound equipment comprises a microprocessor within, or connected to, the host computer.
The microprocessor is the “brain” of an ultrasound system because it performs all the computing tasks to covert the data collected at the peripheral ultrasound system into the images shown on the monitor to the user. In a Doppler ultrasound system with color flow mapping, the microprocessor will process all the data and generate the velocities of the moving tissues and fluid as well as associated colors to show the directional movement of the tissues and fluid.
To properly process this data, the microprocessor comprises memory and software. The software utilizes known algorithms to measure the velocity and to chart the color of the tissue and fluid to depict the directional movement of the tissue and fluid.
Unfortunately, known Doppler ultrasound systems have numerous disadvantages. Microprocessors are not capable of quickly processing the vast information obtained during a Doppler ultrasound. Color flow mapping complicates the problem because producing color images requires a large memory and the processing capabilities that are not appropriate for processing by known microprocessors. Another drawback with Doppler ultrasound systems is despite their accuracy, they are relatively slow in producing images.
Another problem with known ultrasound equipment is the interface between the peripheral ultrasound equipment and the host computer. Specifically, known ultrasound machines utilize an uncommon type of interface which requires the user to modify his personal computer to use it as a host computer.